Corymbia citriodora and Cymbopogon nardus essential oils samples were analyzed by GC and GC-MS and their qualitative and quantitative compositions established. The main component of essential oils of C. citriodora and C. nardus was citronellal, at 61.78% and 36.6%, respectively. The essential oils and citronellal were tested for their fumigant antifungal activity against Pyricularia (Magnaporthe) grisea, Aspergillus spp., and Colletotrichum musae. The minimum inhibitory concentration (MIC) ranged from 100 to 200 ppm for the essential oils and 25 to 50 mg·mL−1 for citronellal. The contact assay using the essential oils and citronellal showed growth inhibition of the three fungal species. However, a concentration of 1.47 mg·mL−1 only reduced the inhibition of Aspergillus growth to 90% at 14 days of exposure. For the fumigant assay, 0.05, 0.11, and 0.23 mg·mL−1 of essential oils and citronellal drastically affected growth of P. grisea, Aspergillus spp., and C. musae. Harmful effects on the sporulation and germination of the three fungi were seen, and there was complete inhibition at 0.15 mg·mL−1 with both oils and citronellal. This showed that the crude component of essential oils of C. citriodora and C. nardus markedly suppressed spore production, germination, and growth inhibition of P. grisea, Aspergillus spp., and Colletotrichum musae.
Aims: To evaluate the activity of cry1Ia gene against cotton pests, Spodoptera frugiperda and Anthonomus grandis.
Methods and Results: Had isolated and characterized a toxin gene from the Bacillus thuringiensis S1451 strain which have been previously shown to be toxic to S. frugiperda and A. grandis. The toxin gene (cry1Ia) was amplified by PCR, sequenced, and cloned into the genome of a baculovirus. The Cry1Ia protein was expressed in baculovirus infected insect cells, producing protein inclusions in infected cells. The Cry1Ia protein has used in bioassays against to S. frugiperda and A. grandis.
Conclusions: Bioassays using the purified recombinant protein showed high toxicity to S. frugiperda and A. grandis larvae. Molecular modelling of the Cry1Ia protein translated from the DNA sequence obtained in this work, showed that this protein possibly posses a similar structure to the Cry3A protein. Ultrastructural analysis of midgut cells from A. grandis incubated with the Cry1Ia toxin, showed loss of microvilli integrity.
Significance and Impact of the Study: The results indicate that the cry1Ia is a good candidate for the construction of transgenic plants resistant to these important cotton pests.
Watermelon (Citrullus lanatus) cultivated in almost all tropical and subtropical regions of the world, has its largest output in China, and then, according to FAO data, Turkey, Iran and Brazil, being
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